intro to med

Question 1

what is a drug

Answer 1

pharmacologically active ingredients
API active pharmaceutical ingredient

Question 2

what is a medicine

Answer 2

means of administrating a drug in a safe and efficient manner - contains drug and excipients

Question 3

what is an excipients

Answer 3

inactive substance used as a carrier for the active ingredients of a medication

Question 4

name the routes of administration

Answer 4

oral,
rectal,
topical,
parenteral,
pulmonary routes,
nasal,
ocular (eyes),
otic (ears)

Question 5

problems associated with different administration

Answer 5

GI -pH,gastric emptying,enzymes,bile
respiratory tract - mucociliary
rectal- poor retention of small dosage, small SA compare to GI tract.

Question 6

A good medicine has (4 things)

Answer 6

dose uniformity - accurate dose
patient acceptability - pleasant to use
stability long shelf life
directions of use

Question 7

name the 3 types of powder

Answer 7

effervescent powders - contain acid and carbonate
dusting powders - talc
powders for syrup - for kids and when formulation are unstable as a solution or a suspension.

Question 8

what is granulation

Answer 8

approach to prevent segregation by forming granules which contain correct ratio of ingredients.

Question 9

ADV of powders

Answer 9

-faster dissolution rate
-more stable than liquid
- convenient for high dose drugs
versatile dosage form - can be customised.

Question 10

DISADVANTAGES of powders

Answer 10

• not suitable for drugs which are inactivated in the stomach
• stability challanges - Difficult to protect hygroscopic and deliquescent substances
• less convenient - carry and prepare

Question 11

what is a tablet

Answer 11

formed by compression of powder or graules.

Question 12

ADVANTAGES of tablets

Answer 12

• accurate dosing
  -long shelf life
  -controlled release options.
  -taste masking

Question 13

DISADVANTAGE of tablets

Answer 13

• difficulty swallowing
  -delayed onset - may take longer to absorb compared to liquids and powders.
  -inactivation in stomach acid.

Question 14

how does a tablet press work

Answer 14

• A die is filled with powder/granules
• mechanical force is applied between upper and lower punches
• Tablet is ejected.

Question 15

what is dissolution and why is it important

Answer 15

e process by which a substance (often a solid) dissolves in a solvent to form a solution.
sold substance need to be dissolved in order to be absorbed into the GI

Question 16

what is the dissolution rate

Answer 16

rate at which drug particles become individually dispersed within a solvent

Question 17

noyes -whitney equation -
4 things

Answer 17

-SA
- solubility in the diffusion layer
-concentration of the drug
-thickness of the diffusion layer

Question 18

tablet excipients

Answer 18

filler/diluent - bulking agent - lactose
disintegrant - enables the breakdown by rupturing the tablet. -starch
absorption enhancers - modulates -permeability of a membrane - surafcants
Binder - mechanical strength - cellulose
dissolution enhancer- increases solubility - magnesium oxide
glidant- improves flowability of the powder - magnesium stearate
lubricant -ensures ejection from the die - magnesium stearate or stearic acid.

Question 19

what are 4 drug release

Answer 19

• immediate release - rapid
  -extended/prolonged release - releases slowly and constant rate
  -pulsatile release - 2 or more pulses
  -delayed release - delayed after some time from administration (enteric coat)

Question 20

what is the enteric coating and when are they used(3) ?

Answer 20

pH sensitive polymers that are insoluble in acid but dissolve in natural or slightly alkaline conditions of the gut.
-drug is inactivated or destroyed by acid in stomach
-drug is irritating to the gastric mucosa
-when bypass from stomach enhances absorption.

Question 21

what is a capsule

Answer 21

edible packages filled with medicine to produce a unit dose

Question 22

what is a solution

Answer 22

mixture of 2 or more components that form a single phase that is homogeneous down to the molecular level.

Question 23

excipients

Answer 23

flavouring agent - palatable
colouring agent - make it attractive
antioxidants - stability
pH adjusters - so site of administration isnt irritated
viscosity enhancer - easy to handle
preservatives - to preserve multidose preparations.
solubility enhancer - maintains solubility of the drug

Question 24

what is a suspension

Answer 24

solid within a liquid vehicle. does not dissolve

Question 25

excipients of suspensions

Answer 25

preservatives - prevent microbial contamination

buffers - maintain pH - suppress solubility

chemical stabilisers -

suspending agents - increase the density of the suspensions or may reduce sedimentation rate

flocculation modifiers - adjust the extent to which floccules form

Question 26

what are the biopharmaceutical considerations ?

Answer 26

• in suspensions and solutions disintegration rate is surpassed.
  bioavaliability - aqueous solutions, aqueous suspensions and then solid dosage.

Question 27

What is an emulsion

Answer 27

dispersions of 2 or more immiscible liquids.
example diazepam

Question 28

how many phases are there in emulsion and what are they

Answer 28

2 phases - water and oil
(o/w) (w/o)
continuous (external) and disperse phases (internal)

Question 29

adv of oil in water phase o/w

Answer 29

mask unpleasant scent and suppress taste
o/w are less greasy so are more accepted by patients in topical drugs.

Question 30

challenges with emulsion stability

Answer 30

• separation into its constituent phases - cracking

Question 31

what effects the stability

Answer 31

choice of oil,
emulsifier,
temperature
droplet size.

Question 32

what excipients are commonly used to improve stability

Answer 32

emulsifiers- surfactants proteins e.g. gelatine
polysaccharides e.g. cellulose
talc or Mg(OH)2.

Question 33

what is it called when a gent has a hydrophobic and hydrophilic part

Answer 33

amphiphiles

Question 34

what is an ointment

Answer 34

semi-solid fatty preparations

Question 35

what are ointments made of
and how does the hydration effect the drug delivery ?

Answer 35

-soft, hard and liquid paraffin.
prevents trans epidermal water loss, hydrating skin.
hydration of the outermost layer increases flux of drug delivered.
can be used to provide prolonged drug delivery

Question 36

what is the chemical stability of o/w emulsion

Answer 36

chemical degradation
high SA.
microscopic oil globules present huge area for light and O2 catalysed reaction.

Question 37

how is this counteracted ?

Answer 37

add oil soluble antioxidant
vitamin E, BHA,BHT

Question 38

microbiological - stability
what is added ?

Answer 38

o/w microbes go well in water phase
use oil phased as food
this destabilises the emulsion
preservatives added

Question 39

why should we be careful with the choice of preservatives ?

Answer 39

it should not partition into oil phase
becomes ineffective
should not interact with the emulsifier
destabilise the emulsion